Mounting for acoustical diaphragms



L LUMIERE Feb. 16; 1932.

MOUNTING FOR ACOUSTICAL DIAPHRAGMS Original Filed May 15 1925 Patented Feb. 16, 1932 PATENT OFFICE LOUIS LUMIERE, OF LYON, FRANCE MOUNTING FOR ACOUSTICAL DIAYHBAGMS Application fled May 18, 1925, Serial No. 30,006, and in France June 7, 1924. Renewed June 18, 1981.

When an acoustical diaphragm is made up of elements each formed of a sheet of elastic material, such as paper, twisted out of its normal plane so as to produce a torsion, as

'5 described in the applicants United States Letters Patent No. 986,47 7 and the diaphragm so formed is mounted in a metal ring, it is found that different hygrometric conditions of the atmosphere exert strong influence 10 upon the diametric dimensions of the diaphragm, when the latter is made of a hygrometric material.

Organic and similar fibre such as paper,

for example, expands and the diameter of the diaphragm increases proportionally to the hygrometrical condition of the air. The metallic ring which holds the diaphragm remains of constant diameter, so that the diaphragm is caused to buckle and pucker and the folds at the centre of the diaphragm are deformed and the reproducing quality of the diaphragm is seriously affected.

The present invention enables this objection to be overcome and the object of the invention is to provide a means for mounting the diaphragm which allows it to expand either towards the centre, if the riphery is held fast, or towards the perip ery whilst the centre remains fixed. In both cases the dia hragm slides between smooth surfaces, which allow of a sliding displacement of the diaphragm in the direction of its diameter, but prevent it from making any movement on its own account in a direction perpendicular to its diameter, that is to say any movements other than the sound vibrations which it is intended to transmit to the air.

The invention may be embodied in various constructions some of which are described 40 below.

Figs. 1 and 2 of the accompanying drawings show respectively in side and front view one way of mounting a diaphragm according to this invention.

Fig. 3 illustrates how a diaphragm may be prepared for carrying the invention into 'eflect in another manner, and this means of mounting it is illustrated in section in Fig. 4.

' Figs. 5and 6 illustrate respectively in section and perspective an alernative method of mounting.

Fig. 7 illustrates a modification of the arrangement shown in Fig. 6.

In Fig. 1 the diaphragm is shown at a, and it will be seen that at b a free space is left about 8 to 10 millimetres in diameter, into which passes the control rod 0. This rod is connected to the diaphragm by means of flat rings d of card, thin metal or other suitable material, the diameter of these rings bein greater than the diameter of the space I). 5 number of these rings of different diameter may be superposed to form a solid body of approximately equal resistance throughout. Two nuts d, d, mounted on the threaded rod 0, allow these rings to be drawn against the diaphragm.

According to another method, when the diaphragm is bein made and its ends have not yet been ointed together by an adhesive but it is still pressed together in the form of a block of parallelopiped form, one or more saw cuts 6, f are made in the end of the block, as illustrated in Fig. 3, by means of a circular saw for example, so that, when the ends of the diaphragm have been joined and the diaphragm is pressed out into the form of a disc and secured by an adhesive at the centre, there are provided one or more grooves at the centre in which there can engage with frictional engagement the annular discs 9, secured by nuts 9 upon the control rod 0 (Fig. 4). The diameter of these discs 9 is chosen somewhat smaller than that of the grooves e, f, so as to allow the diaphragm to expand. The discs 9 may be of stiff card, fibre, wood, ebonite or other suitable material.

It will be clear that any other means of mounting which allows the acoustic vibrations to be communicated to the diaphragm, while leaving the latter free to expand due to the free space left at its centre, will come within the scope of the present invention.

Figs. 5 and 6 show an alternative arrangement. The centre of the diaphragm may be glued or otherwise fixed in any suitable manner upon a cylindrical shaft or hub of wood, card or other suitable material, for example,

tween the thin rings h, h" which hold it in place.

Fig. 7 shows a modification of this arrangement. The metal ring 1 carries a single thin ring it of card, metal, fibre or other suitable material which is slotted radially at equidistant points k, k, is. The diaphragm,-the periphery of which does not quite reach to the bottom of these radial slots, is held between the alternate tongues thus formed in the card board or other ring, the tongues lying alternately on one side or the other of the dia phragm.

' It will be clear that without departing from the scope of the invention modifications of details may be made in the above described arrangements.

I claim:

1. An acoustical diaphragm of large diameter, and formed of hygroscopic material, in combination with means movably holding the diaphragm whereby the diaphragm isrmovable with regard to theholding means in the direction of the plane of the diaphragm.

2. An acoustical diaphragm of large diameter, and formedof hygrosco ic material, in combination with means slida ly holding the diaphragm whereby the diaphragm is slidable with regard to the holding means in the direction of the plane of the diaphragm.

. 3. An acousticaldiaphragm of large diameter, and formed of material subject to dimensional alteration in response to atmospheric conditions, in combination with means movably holding the diaphragm whereby the dia- .phragm is movable with regard to the holding means in the direction of. the plane of the diaphragm, said means resisting anymovement of the diaphragm in a direction perpendicular to its diameter. 4. An acoustical diaphragm of large diameter, and'formed of material subject to.dimen- 81011211 'alteratlon in. response to fitIIlOSPllQIlO conditions, in combination with holding means therefor applied to both'sides of the diaphragm, between which the diaphragm is mounted'for a sliding movement;

5. An acoustical diaphragm of large diameter, and formed of material subject to dimensional alteration in response to atmospheric conditions, in combination with holding means therefor inthe form of flat members lying'on either side'iof the diaphragm, ,be-

tween which the diaphragm is mounted for a sliding movement.

7 6. An acoustical diaphragm of large diameter, and formed of material subject to dimensional alteration in response to atmospheric conditions, in combination with holding means therefor in the form of a flat annular member, part of which lies on one side of the diaphragm and part on the other, and between parts of which the diaphragm is mounted for i a sliding movement.

.7. An acoustical diaphragm of large diameter, and formed 'of'hygroscopic material, in combinationwith a substantially. rigid carrying ring, a member adapted to communicater sound'vibrationsto the diaphragm and means adapted to'allow the diaphragm to.

freely expand and/or contract in the direction of its plane relatively to the rigid carrying ring.

8. An acoustical diaphragm of large diameter, and formed of hygroscopic material, in eombination'with a substantiallyrigid carrying ring, a member adapted to communica'te sound vibrations to the diaphragm and means adapted to allow the diaphragm to freely expand and/or contract in the direction of its plane relatively to the rigid carrying ring and to the said vibration communicating means. r

. 9.13.11 acoustical diaphragm of large diameter, and formed of hygroscopic material, in

combination with peripheral diaphragm car;

rying means adapted to permit of freeexpansion and/or contraction of the diaphragm.

10. An acoustical diaphragm of large diameter, and formed of hygroscopic material, in "combination with diaphragm carrying -means adapted to support movably the outer edge ofsaid diaphragm whereby said diaphragm is capable of free contraction and/or expansion. V

11. An acoustical diaphragm of large diameter, and formed of hygroscopic material, apertured at the center, so that it has an inner and an outer edge, in combination with diaphragm carrying means adapted to support movably one edge of said diaphragm whereby said diaphragm is capable of free contraction and/or'expansion. s

12; An acoustical diaphragm of large diameter, and formed of material subject to dimensional alteration in response to atmospheric conditions, in combination, with a member adapted to communicate sound vibrations to the'diaphragm and meansadapted to allow the diaphragm to move in the direcpheric conditions, andhaving a central aperture in combination with "motion-conveying means Jslidably associated "with an" edgev of said aperture in a direction at an angle to the direction in which'motion is conveyed.

14. An acoustical diaphragm of large diameter, and formed of material subject to dimensional alteration in response to atmospheric conditions, in combination with motion-conveying means slidably associated with said diaphragm in a direction at an angle to the direction in which motion is conveyed and rigidly associated therewith in said last mentioned direction.

15. A loudspeaker comprising a vibrating member, a stationary member surrounding the vibrating member, and a resilient strip fastened to one of said members and loosely in contact with the other member.

16. A loudspeaker comprising a vibrating member, a stationary member, and resilient strips fastened to one of said members and loosely in contact with opposite sides of the other member.

17. A loudspeaker comprising a vibrating member, a stationary member, and resilient strips fastened to the stationary member and loosely in contact with opposite sides of the vibrating member.

18. A loudspeaker comprising a vibratory diaphragm having a flattened peripheral ring, a stationary member surrounding the diaphragm, and resilient strips fastened to said stationary member and loosely in contact with opposite sides of the ring of the vibrating member.

In testimony whereof I have signed my name to this specification.

LOUIS LUMIERE. 

